What you need to know about encryption on your phone

While we wait for the courts or Congress to rule on Apple vs. FBI, learn more about what is and isn't encrypted on your phone, and how you can better protect yourself.

Jason Cipriani
Jason Cipriani
Jason Cipriani Contributing Writer, ZDNet
Jason Cipriani is based out of beautiful Colorado and has been covering mobile technology news and reviewing the latest gadgets for the last six years. His work can also be found on sister site CNET in the How To section, as well as across several more online publications.
Jason Cipriani
7 min read
Jason Cipriani/CNET

The heated and very public confrontation between the FBI and Apple has spurred a lot of talk about encryption, the technology that shields data on phones and other gadgets.

The feds are pushing Apple to find a way to prevent an iPhone 5C from erasing itself after 10 successive incorrect guesses at the passcode. The user of that phone, San Bernardino shooter Syed Farook, used a PIN code to secure his device, and without bypassing that code, the data stored on it is unreadable, thanks to encryption.

If Apple were to disable the auto-erase feature, the FBI could then connect the iPhone to a computer and quickly and repeatedly attempt to guess the passcode -- a technique commonly referred to as a brute force attack -- until the device is unlocked.

Should the FBI prevail and the courts force Apple to comply, the decision could have widespread implications for our daily lives. Apple and fellow technology companies would be forced to create permanent solutions for law enforcement to get around encryption, using what's commonly referred to as a back door.

Alternatively, companies could very well decide the financial burden of maintaining encryption and abiding by law enforcement requests is too much, and give up on adding security features to the devices we've come to rely upon.

With our personal devices carrying more and more of our lives than ever before, it's a good time to look at what is and isn't encrypted and what you can do to ensure your information is safe.

What is encryption?

A fancy word for a basic concept, encryption is the science behind protecting any information stored on an electronic device, be it a phone, a laptop or a server. On a phone that means your photos, text conversations, emails and documents.

Encryption stores information in a scrambled format, typically unreadable by computers or people without a key (which only the device's owner should know) to unlock the data. PIN codes (of numbers, letters or a combination of both) and fingerprints are just two of many examples of keys used to unlock an encrypted device.

Indeed, the practice of encryption is far more technical than requiring a PIN code or fingerprint to unlock a device. Some phone manufacturers, such as Apple, require multiple pieces of information -- one known to the device owner, another embedded in the processor inside the device unknown to anyone -- to unlock data stored within the device.

It's important to note, regardless of the device you're using, data created by third-party applications store information on their own servers, which may or may not be encrypted. Even then, the rules for decrypting data stored on a server are often different than data stored on a phone (see iCloud section below for more information).

In other words, most of what we do on a phone is backed up to a server at some point. That means a copy of your Facebook posts or photo albums, Snapchat conversations, or Twitter direct messages are stored on your device but also on the respective servers for each service.

Essentially, any information stored within an app on your phone that forgoes any sort of connection to a server is encrypted and inaccessible by law enforcement on a locked phone. For example, if an iOS user wanted to keep Notes or Contacts off of Apple severs, he or she would need to disable iCloud sync for the respective app in Settings.

If you've opted not to sync your contacts or calendars through Google or a similar service, relying instead on a local copy of information on your device, that data is encrypted and presumably inaccessible by law enforcement.

How does iOS handle encryption?

Apple began encrypting iOS devices in 2014 with the release of iOS 8. Prior to iOS 8, iOS users were able to set a PIN or passcode to prevent unauthorized access, but some of the data stored on the device was still accessible by Apple when law enforcement presented the company with a valid warrant. A total of 84 percent of iOS devices are running iOS 8 or later.

With iOS 8 and beyond, Apple no longer has the tools required to bypass a device's lock screen and gain access to any data stored on your iOS device. That means items such as call logs, photos, documents, messages, apps and notes are inaccessible to anyone without a device's PIN.

This is an important detail, as it has led to the current situation playing out in public view between the FBI and Apple.

How does iCloud factor in?

Another topic that's come up in the battle between the FBI and Apple is what data stored in an iCloud backup of an iOS can and cannot be accessed by Apple.

Apple's Legal Process Guidelines state iCloud backups are encrypted and stored on the company's servers. However, unlike an encrypted device, Apple can access information stored within a backup. Specifically, it's possible for Apple to provide authorities with "photos and videos in the users' camera roll, device settings, app data, iMessage, SMS, and MMS messages and voicemail," as detailed in Section J.

What about encryption on Android?

As with all things Android, there's a long list of caveats regarding encryption on an Android device.

Android manufacturers use different processors and components, each requiring custom software and backup services outside of what Google originally designed Android for. It's the key selling point of Android over iOS, as Android fans are quick to espouse. And they're not wrong. However, each change can introduce unintended security issues outside of Google's control.

Google first provided the option for users to opt into encrypting their devices in 2011. At the time, the option was strictly up to the user, leaving the manufacturer out of the equation.

Toward the end of 2014, though, the company released Android 5.0 Lollipop with the default setting of encryption turned on. But phone makers didn't have to enable encryption to be default when they made phones; it wasn't a requirement of Google, and in the end, most OEMs left the setting turned off, citing performance issues as the reason.

Then, with the release of Android 6.0 Marshmallow in 2015, Google started requiring manufacturers to enable encryption on all devices out of the box. There is, of course, an exception to the rule: Google allows phone makers to disable the feature on what amounts to entry level, and thus often slower devices. For those who want a more technical explanation, read section "9.9 Full-Disk Encryption" of this document.

Once an Android device is encrypted, all data stored on the device is locked behind the PIN code, fingerprint, pattern, or password known only to its owner.

Without that key, neither Google nor law enforcement can unlock a device. Android security chief Adrian Ludwig recently took to Google+ to refute a claim of a back door into Android: "Google has no ability to facilitate unlocking any device that has been protected with a PIN, password, or fingerprint. This is the case whether or not the device is encrypted, and for all versions of Android."

Nevertheless, each phone manufacturer is able to alter Android, customizing its look, adding or removing features, and in the process potentially introducing bugs or vulnerabilities authorities can use to bypass Android's security features.

So how do you know if you've got encryption working?

Android users can check the encryption status of a device by opening the Settings app and selecting Security from options. There should be a section titled Encryption that will contain the encryption status of your device. If it's encrypted, it will read as such. If not, it should read similar to "encrypt device." Tap on the option if you want to encrypt your device, but make sure to set aside some time -- encrypting a device can take upwards of an hour.

Google's backup service for Android devices is optional for device manufacturers and application developers. As with Apple's iCloud Backup practices, data within a backup stored on Google's servers is accessible by the company when presented with a warrant by law enforcement. However, because the backup service is opt-in by developers, it may not contain data from every app installed on your device.

What can you do to better protect your data?

Android users should enable encryption and set a PIN code or alphanumeric passcode. iOS users, setup Touch ID and use an alphanumeric passcode containing at least six digits. The longer password is a hassle, yes, but with Touch ID enabled, you shouldn't have to enter it too often.

If the FBI succeeds in forcing Apple to bypass a device's lock screen timeout, it would take five and a half years for a computer to crack a six-digit alphanumeric passcode, according to Apple's iOS Security Guide (see page 12).

As for protecting data stored in backups on Apple's or Google's servers, you can start by disabling iCloud backups by opening the settings app, selecting iCloud, followed by Backup and sliding the switch to the Off position. Apple also allows you to delete iCloud backups from your account through the iCloud settings on your iOS device by opening Settings > iCloud > Storage > Manage Storage.

On Android, the process for disabling backups will depend on the device you're using, but generally the setting is found in Settings app under Backup & Reset. You can remove backed-up data from Google's servers under the Android section in your Google Dashboard.